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constraints

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charles1309
Starting Member

15 Posts

Posted - 2007-11-20 : 06:52:23

hi there,

i have added my tables and defined foreig keys and primary keys for my table, but when i try to put the data it gives me some error reagards to parent key..and it wont let me drop the table... can anybody tell me how to drop the foregin key..i have tried (

ALTER TABLE module DROP CONSTRAINT ATTENDANCEID_FK;)
this formula and it wont work,

heres my tables and relationships:

CREATE TABLE ATTENDANCE
(ATTENDANCEID char(4) NOT NULL,
StudID char(4) NOT NULL,
ModuleID char(4) NOT NULL,
Week1 VARCHAR(10),
Week2 VARCHAR(10),
Week3 VARCHAR(10),
Week4 VARCHAR(10),
Week5 VARCHAR(10),
Week6 VARCHAR(10),
PRIMARY KEY (ATTENDANCEID));

ALTER TABLE ATTENDANCE
ADD FOREIGN KEY (studID) REFERENCES student(studID);
ALTER TABLE ATTENDANCE
FOREIGN KEY (moduleID) REFERENCES module(moduleID));

insert into ATTENDANCE values
('F1','A1','E1','Yes','Yes','Yes','Yes','Yes','Yes');
insert into ATTENDANCE values
('F2','A2','E2','Yes','No','Yes','Yes','No','Yes');
insert into ATTENDANCE values
('F3','A3','E2','Yes','Yes','Yes','No','Yes','Yes');
insert into ATTENDANCE values
('F4','A4','E2','Yes','Yes','Yes','Yes','No','Yes');
insert into ATTENDANCE values
('F5','A5','E1''Yes','Yes','No','Yes','Yes','Yes');
insert into ATTENDANCE values
('F6','A6','E2','Yes','Yes','Yes','Yes','Yes','No');
insert into ATTENDANCE values
('F7','A7','E1','Yes','Yes','Yes','Yes','No','No');
insert into ATTENDANCE values
('F8','A8','E2','Yes','Yes','Yes','No','Yes','Yes');
insert into ATTENDANCE values
('F9','A9','E3','Yes','Yes','No','Yes','Yes','Yes');

CREATE TABLE MODULE
(ModuleID char(4) NOT NULL,
ATTENDANCEID char(4) NOT NULL,
ModuleName varchar(45),
ModuleCode varchar(6),
PRIMARY KEY (ModuleID));

ALTER TABLE MODULE
ADD FOREIGN KEY (attendanceID) REFERENCES attendance(attendanceID);

insert into MODULE values
('E1','F1','Workshop Research and Project Implementation','Im3023');
insert into MODULE values
('E2','F2','Advanced Database Development','SD3042');
insert into MODULE values
('E3','F3','Advacned Information Systems Develpment','SD3043');

charles

DonAtWork
Master Smack Fu Yak Hacker

2167 Posts

Posted - 2007-11-20 : 07:41:24

1) there are errors in your script.
2) where is table 'STUDENT' that is a reference for one of your FKs?
3) Normalize your data

[Signature]For fast help, follow this link:
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nr
SQLTeam MVY

12543 Posts

Posted - 2007-11-20 : 08:22:29

You need to find the name for the forein key constraint to drop it. It will be system generated as you haven't given it a name.

==========================================
Cursors are useful if you don't know sql.
DTS can be used in a similar way.
Beer is not cold and it isn't fizzy.

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